Liz, I've been thinking about the best way to illustrate the core of the MGA and Olympia arguments. Perhaps this will help.
The Olympia idea is indeed a "baroque" construction as the paper nicely puts it, but I suspect Maudlin was trying to illustrate what amounts to a simple intuition, namely that when a specific calculation is carried out (in any medium), the machine carrying it out is physically like Olympia: there is a single sequence of steps in which one can ignore the inactive counterfactuals completely. All the complexity and intelligence is in the capacity of the computer to handle many possible inputs, yet when any specific input goes through, we can always think of the computer as an Olympia that can only do that one task. To realize this we can imagine that we remove all the circuits and pathways that weren't actually employed. All the baroque elements of hoses, troughs and rusting gates really just serves to make this point particularly clear. Another way to think about this in purely logical/arithmetic terms is to imagine a program to calculate the sum of any two positive integers x and y. Imagine the program does this by adding 1 to x sequentially, each time asking itself have I done this 'y' times yet? If yes, stop and output x, if no, do it again. For the inputs 1 and 2, we get: x=1, y=2 x=x+1=2, count=1. Is count=y? no, so repeat x=x+1=3, count=2. Is count=y? yes, so output output x (3) Now I want to remove the capacity to handle counterfactuals, that is to say, I want to remove all decision making logic from the machine but still let it output 3 for the inputs 1 an 2. How do I do it and still get the result of 3 for those inputs. The answer depends on whether the machinery that performs each step of the calculation is reused or not. If it isn't, then the size of the calculation I can perform will be limited by the size of the machinery (I need to repeat the mechanism y times to add the number y to x), but if I imagine I can manufacture new machinery on the fly or simply have an infinite machine, then this is not an issue. If I don't reuse the machinery, then the way to remove the capacity to handle counterfactuals is to solder shut the logic gates such that the machine (program) now looks like: x=1, y=2 x=x+1=2 repeat x=x+1=3 output output x(3) We can see that it becomes a machine for counting to 3. This is Olympia (on a very small scale). However if I *do* reuse the machinery, then I can't solder the logic gates in any fixed position because I still need to know when to stop and output the result. In this case I simply hard wire the machine to run the addition step exactly twice before outputting, which is exactly what the 'filmed graph' scenario does - it removes the logic gates and remotely controls the operation of the machine in a fixed, mindless fashion. Interestingly this is what robots do in manufacturing plants. Because the routine is the same each time, there's no need for all that human counterfactual processing capacity - just record the sequence and output it over and over. The reason why the MGA is possibly less convincing (superficially) is that it's not obviously the same physical process being carried out when the recorded light beam activates the nodes as when they are activated by the logic of the connections between them. Maudlin removes that possible (meretricious) objection by having machinery that can't be reused. That way he can more easily show the physical equivalence of the process in both cases. Finally though, there is another possible objection even if we accept this type of argument. That is to say that, sure, consciousness must supervene on the logic not the physical operation. However we still insist that physical instantiation of the logic is required to instantiate the relevant consciousness. i.e., consciousness supervenes on logic + matter, or the logical organization of matter. This would be Brent's position I believe. Now Bruno counters this by calling it disgraceful and ad hoc, yet perhaps we can read from the uncharacteristically emotive adjective that he senses a weakness here. To be clear, I tend to agree with Bruno's conclusion, but I fear that the acceptance of this theory will always stumble over this point, because for materialists there is already some assumed ontological magic to matter. It's what "puts the fire in the equations" or whatever. Bruno's theory gets around the magic of material instantiation, the "brute fact" of something happening to exist physically, by showing how everything is instantiated in some relative perspective interior to arithmetic. That is very elegant and nice. But to people deeply inculcated in the cult of Matter, that elegance will be invisible. They *trust* matter and the assumption that the ultimate explanation of things will keep some kind of objective "stuff" at its centre runs very deep. Plus I don't believe it can be said that Bruno's theory makes everything clear with respect to consciousness, as I've argued elsewhere. We might hope that a theory based purely on a mathematical ontology would not have to resort to an apparently magical proposition like there *being* an interior perspective to mathematics. We have no reason to imagine that there should be one, other perhaps than the fact that *we* are conscious. So the description of what mathematics is has this dimension of interiority added it to by the comp assumption - and the only answer as to "why" is that there is no answer. So some magic brute fact remains, albeit within a nicely unified ontological framework. I would say only that I have little reason to go on thinking of this mathematical Platonia as purely mathematical. Perhaps all is subsumed within consciousness itself, and mathematics is an emergent phenomenon so long as our consciousness remains limited within Form, which by its nature demands self-consistency. Sheesh, getting very mystical here. Enough. On Monday, August 11, 2014 8:38:00 AM UTC+10, Russell Standish wrote: > > As long, long time promised, I now have a draft of my "MGA revisited" > paper for critical comment. I have uploaded this to my blog, which > gives people the ability to attach comments. > > http://www.hpcoders.com.au/blog/?p=73 > > Whilst I'm happy I now understand the issue, I still not happy with > how I've expressed it - the text could still do with some work. > > So let the games begin! > > -- > > ---------------------------------------------------------------------------- > > Prof Russell Standish Phone 0425 253119 (mobile) > Principal, High Performance Coders > Visiting Professor of Mathematics hpc...@hpcoders.com.au > <javascript:> > University of New South Wales http://www.hpcoders.com.au > > Latest project: The Amoeba's Secret > (http://www.hpcoders.com.au/AmoebasSecret.html) > ---------------------------------------------------------------------------- > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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